Sydney, July 9 - First-time older mums cope surprisingly well with the exacting demands of pregnancy, compared to their younger counterparts, but are more anxious about their unborn baby's well-being, according to new research.

'Generally it has been thought that older mums may not cope with the physical demands of pregnancy as well as younger mums, or they may be very anxious or find it difficult to cope with lifestyle changes,' said Macquarie University psychologist Catherine McMahon.

'But what we found was that even though there are some differences, older mums were generally adjusting well.'

The study followed women of different ages - in their 20s, 30s and 40s - from their third trimester of pregnancy until four months after the birth of their baby. In a first, the researchers looked both at age and infertility as factors influencing adjustment.

The aim of the study was to assess the impact of parental age and IVF conception on physical health, well-being and psychological adjustment during the transition to first-time parenthood.